In related art, a wireless communication device which is connected to a network, such as a public wireless network, is becoming widespread. Further, since 2002, a mobile phone service of a 3G system (In Japan, referred to as the third generation) has been started. At the beginning, the main application of mobile phone service was voice, e-mail or the like using small capacity packets. However, with the introduction of HSDPA (High Speed Downlink Packet Access) or the like, the usage behavior of users kept changing towards downloading comparatively large-sized packets, such as downloading music files or watching moving images.
Further, in recent years, in a mobile environment, wireless communication devices, such as smartphones, with which the user is able to enjoy a variety of applications are becoming widespread. In this way, according to the wide use of wireless communication devices such as smartphones, the traffic of packet communication has increased rapidly. In this respect, it may be important to efficiently use wireless communication resources.
For example, there is proposed a communication system in which a server estimates the amount of free space, and notifies the wireless communication device of the estimated amount. (for example, refer to PTL 1).